electowiki

Participation criterion: Difference between revisions

Page Discussion

Participation criterion (view source)

Revision as of 19:10, 14 May 2020

995 bytes added ,  4 years ago
Make more clear what Participation implies
VisualWikitext
(Undo revision 11046 by Kristomun (talk) Feel free to undo this if you disagree with this as well.)
Tag: Undo
(Make more clear what Participation implies)
Line 1:
{{wikipedia}}
 
The '''participation criterion''' is a [[voting system criterion]] applicable to both single and multiple winner [[ranked voting system]]s. A method that passes this criterion ensures a voter that it's always better to cast a full honest vote than to not show up for the election at all. It does this by guaranteeing that adding a ballot can never change the winner from someone who is ranked higher on that ballot to someone who is ranked lower.
This is the criteria that there is no strategic advantage to not vote. Typically a voter does not know they are in this situation and if they do they can potentially avoid the problem with [[Tactical voting]]
 
While the criterion ensures that a voter can't benefit from staying home rather than voting honestly, a voter may do even better by engaging in [[tactical voting]]; participation does not imply that the method is strategy-proof.
 
== Statement of Criterion ==
 
For deterministic single-winner methods, the criterion is defined as follows:
{{definition|Adding one or more ballots that vote X over Y should never change▼
 
the winner from X to Y.}}
▲{{definition|Adding one or more ballots that vote X over Y should never change the winner from X to Y.}}
 
For multi-winner methods and methods that involve an element of chance, the definition is:<ref name="Woodall-Monotonicity">D R Woodall, [http://www.votingmatters.org.uk/ISSUE6/P4.HTM "Monotonicity and Single-Seat Election Rules"], ''[[Voting matters]]'', Issue 6, 1996</ref>
 
{{definition|The addition of a further ballot should not, for any positive whole number k, reduce the probability that at least one candidate is elected out of the first k candidates listed on that ballot.}}
 
== Variants ==
Line 22 ⟶ 29:
== Complying Methods ==
 
This Criteriacriterion is important in the context of the [[Balinski–Young theorem]]. Failing the participation criterion is an an example of failing [[Population monotonicity]].
 
[[Plurality voting]], [[Approval voting]], [[Cardinal Ratings]], [[Borda count]], and Woodall's [[Descending Acquiescing Coalitions|DAC]] and [[Descending Solid Coalitions|DSC]] methods all pass the Participation Criterion. [[Condorcet method | Condorcet methods]], [[Majority Choice Approval]], and [[IRV]] fail.
 
All Monroe type Multimulti-member systems fail participation.
 
''Some parts of this article are derived with permission from text at http://electionmethods.org''
Line 53 ⟶ 60:
*[[Favorite Betrayal criterion]]
*[[Summability criterion]]
 
== References ==
<references/>
 
== External links ==
 
* [http://electionmethods.org/ Election Methods Education and Research Group]
* [http://www.mcdougall.org.uk/VM/ISSUE6/P4.HTM Woodall's DAC method]
 
[[Category:Voting system criteria]]
Kristomun
1,196

edits

Retrieved from "https://electowiki.org/wiki/Special:MobileDiff/11126"